The drawbacks of conventional defrosting methods can be avoided thanks to the
ability of radio frequency (RF) to rapidly generate heat volumetrically within the
product. The heating process is fast, uniform and controlled, resulting in a
significant reduction of drip losses and minimising product deterioration due to
bacterial growth. The RF heating method offers flexibility in the production
scheduling and is the ideal solution for many tempering, softening and defrosting
processes.

The product is placed on the machineâ€™s conveyor belt and is transferred
continuously through the RF unit (tunnel) passing between upper and lower
metallic plates. These plates (also called electrodes) form an electrical capacitor
and the product in between the plates becomes the dielectric element of that
capacitor. The electrode plates are connected to a radio frequency generator
oscillating at a frequency of several million cycles per second.

When the RF generator applies high frequency alternating voltage between the
capacitor plates, the dipolar water molecules of the frozen product will vibrate and
rotate attempting to align themselves according to the fast changing opposite
plates polarities. This phenomenon causes intermolecular friction, which will in
turn generate heat rapidly and uniformly within the whole product mass regardless
of its size, weight, shape and thermal conductivity.

The amount of heat generated inside the product and the defrosting time are
accurately controlled through the voltage applied on the electrode plates and the
speed of the conveyor belt

Benefits of the RF defrosting method

Defrosting is achieved in minutes rather than hours/days, even for large product
blocks and, if necessary, directly inside packaging used for storage or retail
distribution (carton boxes, polyethylene bags, etc.);

The processing speed and uniformity minimise the risk of product degradations
(drip losses, deterioration of sensorial, chemical and physical characteristics,
bacteria growth, etc.), thus helping to preserve at its best the product quality,
especially in the case of heat-sensitive products;

The product can be obtained at the correct temperature needed for the next stage
of processing;

Thanks to the high processing speed, radio frequency defrosting can be carried
out continuously, with significant logistical advantages in product handling and
production scheduling. The production can be organised according to "just-in-
time" criteria - a great advantage in the case of sudden orders, last-minute
changes in the order or under processing, etc.;

Weather and external ambient conditions do not affect the process, so that it can
be controlled accurately and consistently;

Radio frequency equipment requires much less floor space compared to the
traditional, large defrosting rooms / equipment; relevant processing costs can also
be reduced drastically compared to conventional techniques.